Manufacture of nitric acid.



h (Phase '1'),

. @Fll ltlt GABL UEBEL, QEF GEMTAIQ'Y.

MfiN' 'J'll-ACTURE OF hlllTRl'C ACID.

Ilt'o Dremng.

To aZZ whom it may concern: t

Be it known that I, CARL UEBEL, chemist, a subject of the German Emperor, and e resident of Bergstrasse 34, Heidelberg, Baden,

5 Germany, have invented certain new and useful Improvements in the Manufacture of Nitric Acid, of which the following is a specification,

This invention relates to the manufacture 1c of nitric acid from'nitretes and sulfuric eciol.

. u In the processes for manufacturing nitric eci6. from nitrates and sulfuric acid as heretofore lmown and used a mixture of mtrote 2.5 end sulfuric ecitl in amount corresponding to the formation of bisulfctc or sullete has always been introduced into the reaction @ember either intermittently or continuously, enol by gradually increased heating transformation of the nitrate by sulfuric acid and the zlistilling off of the nitric acid has been effected. These processes, however, have this drawback that, firstly, only it pert'ol the nitrate is transformed by the sulfiuric acid, the rest being clcposited on the bottom of the reaction chamber as crystellme crust, 'lhis nitrate crust easily becomes superheated and thereby causes the foaming over of the reaction chamber or en 3o QXPlOSlOIl like development of gases Whereby notwithstanding the most careful super- A vision of the retort firing there is caused a. frequent poffin out of nitric acid fumes and 'in connection t' erewith (longer to the Workmen. Secondly, in consequence of the superheeting of the nitrate crust on the botton of the retort, dcc'ompositmn takes place which causes losses in n1tr1c acid. These disadvantages are now to be obviated by" 40 the present invention. According to said invention the entire amount of sulfuric acid required for decomposition of the nitrate is first of all charged into the reaction chem her with only part, for instance half, of the nitrate charge and is heated therein to a Speciflction of Letters Patent.

Petohtcclglune 8, 11915.;

Application filed Fseptember 16, 1913. Serial No. 790,137.

is raised. (Phese 2). Now, if in the second phase only highly concentrated acids are to be distilled o the raising of temperature must only be carried to such a, point that the Water contained in themess ie not yet driven oil. Now, when the distillin ofi of the concentrated nitric acid is finl ed, the residue of the react-ion of the second phase or stege of the process is removcrl to at special reaction chamber Where, under it further increase or" temperature, the Water containcbl and the nitric we are Mme of. (Phase 3).

will now be illustrated in detail in the following example, in connection with Chili scltpeter. For carrying out the proccssthe threcpen system is most suitable, two of which are connected in parallel Whereas the third is connected with the two other pens.

All three fpens are heated in e lmown man ner. Pro erably the Work is done in such The practical carrying out of the process a way that while in the first pan onephese or stage of the process is taking place in the second pen the nextphase or stegc is teking place Whereas the third pen is used for the last stage, or the driving 01E of the rest of the nitric aciol. Assuming the pen il to be recharged: without necessitating e, cooling down of said pan, e portion, up to half, of the seltpeter charge is gradually introduced.-

-This is done best by means of a. mechanical feed conveyor or the like, while at the same time the total amount of sulfuric acid requirecl for the conversion of the total charge of! seltpeter is introduced. The charging of seltpeter is so regulated that always an excess of sulfuric acid is present in the pan. The temperature in the pen during this period of distillation is brought to andmaintained at about 140 centigrade.- A13 cording to the progress'of the reaction the charge of saltpeter and sulfuric acid can be slowed down or speeded up. A transformation according to the following equation takes place: NaNO +QH SO NcHSO,+l-LS0 +HNO Now as with a prevailing temperoture of about 140 the Water present is retained by the excess of'sulfuric ecid, only highly com. ccntratecl mllllfi ecid ovemthefreclclne i'oc ' the sulfuric acid is always in excess, heatmg to a, temperature at Which the'nitrate "rhea; introduced will be decompose but wrzieh will allow only. nitric acid maimder ,0f- ..the nitrate, decempesitiom the introduction ef the of high percentage tq distile off then adding the reand. efiecting its" .femeinder of. the nitrite being likewi gradual. t I

1 GAR-L UEBE In the presence of 'GEORG Lorz, GOTTLIEB WERNER. 

